Pump assembly



Feb. 21, 1967 E. J. SCROGGINS PUMP AS SEMBLY 4 Sheets-Sheet 1 Filed April 20, 1965 INVENTOR.

ELVA J. scRoscms \pll f ni hnuvvili\tiih Ill El'llllllillllllhll lb 1967 E. J. SCROGGINS 3,304,371

PUMP ASSEMBLY Filed April 20, 1965 4 Sheets-Sheet 2 FIG. 7

lNVENTOR.

ELVA J. SCROGGINS Feb. 21, 1967 E. J. SCROGGINS PUMP ASSEMBLY Filed April 20, 1965 4 Sheets-Sheet 3 FIG. 8

INVENTOR. ELVA J. SCROGGINS F5 A ma? r/mwmui mm Feb. 21, 1967 E. J. SCROGGINS PUMP AS S EMBLY Filed April 20, 1965 United States Patent 3,304,871 PUMP ASSEMBLY Elva J. Scroggins, 528 Doris St., New Iberia, La. 7056!) Filed Apr. 20, 1965, Ser. No. 449,435 13 Claims. (Cl. 163-46) The present invention relates to a hydraulically actuated reflex pump and more particularly to a pump for producing fluid from bore holes of wells without requiring a pump rod extending from the top of the well to the pump cylinder.

Heretofore, various types of pumps have been provided for producing fluid of the desired character from a formation but none have been entirely satisfactory, particularly when the location of the pump may vary in the well between wide limits. Further, it has been diflicult to remove a pump from the well tubing because of the large numbers of pipe sections required to support the pump at the proper depth and it has been very timeconsuming to install or remove the pumps known in the prior art.

An object of the present invention is to provide a pump which can be located at practically any depth in a well and serve to produce the desired fluid from the formation and which will avoid the objections of the prior art.

Another object is to provide a pump structure which is operated by pressure on the fluid in the well.

A further object is to provide a pump which is positively operated in one direction and operated by a variable resilient force in the opposite direction so that operating force need be applied in only one direction on the pump assembly.

Other and further objects will be apparent as the description proceeds and upon reference to the accompanying drawings, wherein:

FIGURE 1 is a diagrammatic illustration of a section of a well having a casing, tubing, and a pump assembly of the present invention in the tubing with a packing seal between the tubing and the casing just above the portion of the formation from which the fluid to be produced is located, parts being broken away and parts shown in section to illustrate the operation with the pump being actuated by increased fluid pressure on the liquid in the tubing and forcing the produced liquid upwardly in the well in the annulus formed between the tubing and the casing.

FIGURE 2 is a section through the top sub taken on line 2-2 of FIGURE 1 and showing a valve core and a seal cap closing the passage for gas into the top cylinder.

FIGURE 3 is an enlarged quarter section of the lower end of the top sub showing the passage for conducting gas into the top cylinder and showing the seal of the top cylinder with the top sub.

FIGURE 4 is a fragmentary view of the lower portion of the top cylinder, the lift piston therein, the cylinder connecting sub, the center connecting sub with the lower cylinders secured therein and showing a portion of the tubing and the seating nipple of the tubing with the valves in open position.

FIGURE 5 is a horizontal section taken substantially on 5-5 of FIGURE 4 and FIGURE 1 showing the pivotal connection of the pivoted valve and the spring operation thereof.

I 3,304,871 Patented Feb. 21, 1967 FIGURE 6 is a horizontal section taken on line 6-6 of FIGURE 4 showing the passages for produced fluid from the lower cylinder to the annulus outside of the tubing connecting nipple.

FIGURE 7 is a fragmentary elevation with parts broken away showing the pump piston and the check valves in the piston and in the bottom sub to assure movement of the produced fluid toward the surface.

FIGURE 8 is a diagrammatic illustration of another modification of the invention in which the pump is positively actuated in one direction by increasing the pressure of fluid in the space between the tubing and the casing with the produced fluid passing upwardly through the tubing with parts shown in elevation and parts in section.

FIGURE 9 is an elevation with parts broken away and parts shown in section of the top sub, the upper connecting sub with a check valve therein and with a valve core in a tube with suitable passages to apply gas under pressure to the top cylinder connected to the sub and showing the inner barrel through which produced fluid passes upwardly and also showing passages in the top sub communicating therewith for conducting fluid into the tubing.

FIGURE 10 is a section taken on line 10-10 of FIG- URE 9 showing the passages for produced fluid.

FIGURE 11 is a section taken on line 11-11 showing the tube passing through the produced fluid passage in the upper connecting sub for conducting gas under pressure into the annular space between the upper cylinder and the inner barrel.

FIGURE 12 is a fragmentary view showing the connection of the upper cylinder to the connecting sub and the connection of the connecting sub to the lower cylinder and showing the seating nipple with the fluid passages therein and also showing the tubular connecting rod between the lift piston of the upper cylinder and the pump piston of the lower cylinder.

FIGURE 13 is a fragmentary elevation with parts in section and parts broken away showing the bottom sub, the pump piston and the check valve and showing the means for connecting the lower end of the tubular connecting rod to the check valve and pump piston.

Briefly, the present invention is a pump assembly which includes a top sub having means for attachment to a cable for lowering of the assembly into the tubing of a well and attached to such top sub is an upper cylinder having means to insert and retain gas under pressure therein with a lift piston mounted in the upper cylinder and forced downwardly by the gas pressure and forced upwardly by the pressure on the liquid in one of the spaces consisting of the annular space between the casing and the tubing and the space within the tubing. The upper cylinder is connected to a center connecting sub either directly or by means of an upper cylinder connecting sub and a connecting rod passes through the center connecting sub in fluid tight relation and carries at its lower end a pump piston which operates in a lower cylinder connected to the center connecting sub. Check valve means are provided in the pump piston and in either the bottom sub or the top sub. Valves provide communica tion between the annular space between the casing and the tubing and the space within the tubing or within one of the cylinders whereby the flow of liquid is prevented until the valves are opened by a boss in the center connecting sub engaging cams on the valves as the center t2 connecting sub is seated in the seating nipple. Suitable stop means are provided in the seating nipple which also connects adjacent sections of tubing and the center connecting sub to assure that the valve opening boss is in the proper position to open the valves.

In operation of one modification (after the gas under pressure is inserted in the top cylinder), fluid under pressure within the tubing has additional pressure applied thereto thereby raising the lift piston within the upper cylinder against the pressure of the compressed gas and upon release of the pressure in the tubing the lift piston and the pump piston are returned to the lower position and the cycle is repeated with the produced fluid passing outside of the casing through the valves in the seating nipple and thence to the surface.

In the other modification, the pressure of the fluid in the annulus formed by the casing and the tubing is increased to raise the lift piston in the upper cylinder to thereby raise the pump piston by means of the tubular connecting rod and the produced fluid is pumped through the tubular connecting rod and into a barrel in the upper cylinder and thence through a check valve and passages in the top sub and thence through the tubing to the surface.

Referring more particularly to the form of the invention shown in FIGURES 1 to 7, inclusive, a casing of conventional form has the tubing 16 therein with a packing 17 sealing the space between the casing and the tubing so that produced fluid from the formation must enter the tubing from beneath the packing 17. A top sub 18 is provided with a boss 19 to which a cable can be secured in a well known manner and such top sub is externally threaded at its lower end and threadedly connected to an upper cylinder 20 and threadedly connected to a center connectthrough an L-shaped passage 21 in the horizontal section of which is a conventional valve core 22 which is additionally sealed by a cap 23 having an O-ring groove with a sealing O-ring 24 therein, whereby gas under pressure can be forced into the cylinder 20 above the piston 25 which is sealed by means of a supply of oil 26 thereon and sealing piston or O-rings 24 in suitable grooves.

A connecting rod 27 threadedly attached to the piston 25 passes through an O-ring seal in an upper cylinder connecting sub 28 which is threadedly connected to the upper cylinder 20 and threadedly connected to a center connecting sub 29. Passages 28A, 28B provide for the passage of fluid from the tubing 16 against the bottom of the piston 25 so that when the pressure in the tubing exceeds the gas pressure in the cylinder 20, the lift piston 25 will be raised, thereby moving the connecting rod upwardly.

Adjacent sections of the tubing 16 are connected by a pump seating nipple 30 which is threadedly connected to the adjacent sections of tubing and is adapted to receive the center connecting sub 29 and suitable seals are provided by means of O-rings 24 or the like on both sides of passages 31, valve seat 31A and radial passage 31B and the valve seat 31A is normally closed by the associated valve head on the pivoted valve 32 which is normally closed by the spring 32A with two valves being shown. To protect such pivoted valves 32 from damage during the insertion in the casing, the pump seating nipple has outwardly extending lugs 33 of a size to project outwardly beyond the valves 32 to prevent the valves 32 from contacting the casing.

The valves are opened by a valve operating boss 34 which engages the stern of the valve in the seated position of the center connecting sub in the pump seating nipple and to assure that the boss 34 is in proper position cooperating stops 35 and 35A of conical shape interengage as shown with the taper of the surface 35 on the pump seating nipple being slightly more open to assure release of the pump assembly when it is desired to raise the pump assembly by the cable attached to the boss 19 of the top sub.

The lower cylinder 36 is screw threadedly attached to the center connecting sub 29 with the connecting rod 27 extending therein and screw threadedly attached to a connecting rod-plunger connecting sub 37 which is screw threadedly connected to the pump piston 38 with the connecting rod-plunger connecting sub 37 having a cage formed therein containing a ball 39 seated in a valve seat 46 with the ball 39 closing the axial passage 41 in the piston 38, whereby when the piston 38 is raised liquid thereabove will be pumped upwardly through the space between connecting rod 27, lower cylinder 36, connecting sub 29 through the passages 31B, 31 and 31A to the annular space between the casing 15 and the tubing 16.

Threadedly secured to the lower end of the lower cylinder 36 is a bottom sub 42 having an axial passage therethrough which communicates with an axial passage in the lower check valve seat 43 which passage is closed by a ball 43A retained on the seat 43 by a cage 43B having fluid passages the-rethrough with suitable sealing O-rings serving to maintain a fluid-tight connection between the parts.

It will be apparent from the above description that the pump action is obtained by increasing the pressure of liquid in the tubing 16 thereby forcing the liquid through the passages 28A in the upper cylinder connecting sub 28 and forcing the lift piston 25 upwardly against the calculated gas pressure in the upper cylinder, thereby moving the connecting rod 27 and the pump piston 38 connected thereto upwardly forcing the liquid above the check valve 39 upwardly through the passages 31, 31A and 31B and thence upwardly in the annular space between the casing 15 and the tubing 16 to the surface where the produced fluid is collected. By alternating the pressure in the tubing liquid, the pump action is repeated and the check valve 43A prevents retrograde movement of the liquid being produced. The packing seal 17 assures that the produced fluid is located below such packing 17.

Referring more particularly to FIGURES 8 to 13, the modification shown therein includes a top sub 18A having a cable connecting boss 19 thereon and being provided wtih axially extending passages 18B communicating with the tubular bottom end thereof threaded on its inner periphery to receive an upper connecting sub 50 threaded therein with the sub 50 receiving a check valve 43 similar to that shown in FIGURE 7 with a ball 43A retained in position by a cage 43B with the connecting sub being tubular and threadedly connected to the upper cylinder 20A and an inner barrel 20B with suitable sealing rings 24 provided to assure liquid-tight and gas-tight seals.

To supply gas to the annular space between upper cylinder 20A and inner barrel 2013, a passage 21A extends upwardly into a transverse passage which receives a tubular valve core receiving nipple 51 which is fluidtightly sealed by O-rings 24, as shown, and receives the usual valve core 22 and the sealing cap 23 previously described, whereby gas under pressure can be forced into the upper cylinder 20A and retained therein.

Within the cylinder 20A is an annular piston 25A having sealing rings on its external periphery engaging the upper cylinder 20A and sealing rings on its inner periphery engaging the inner barrel 20B with a tubular connecting rod 27A extending downwardly therefrom and secured to the piston and such connecting rod passes through the center connecting sub 29A with the connecting sub being threadedly secured to the upper cylinder and to the lower cylinder 36A by threaded sealed connections. Sealing O-rings 24 on the inner periphery of the center connecting sub 29A provide a fluid-tight seal against the outer periphery of the tubular connecting rod 27A and such tubular connecting rod is secured to a plunger connecting sub 52 which in turn is connected to a lower check valve body 53 which loosely receives the check ball 54 which closes the axial passage through the pump piston 55 whereby the pump piston will raise produced fluid through the passage in tubular connecting rod 27A through ports 56 from the lower cylinder 36A and thence through the inner barrel 20B to the upper connection sub 50 and through the check valve assembly 43, 43A, 43B and thence through the passages 18B in the top sub 18A and thence through the tubing to the surface. The pressure is applied to the fluid in the casing 15 lying in the annular space between such casing 15 and the tubing 16 with sufficient force to move the lift piston 25A upwardly, thereby raising the pump piston 55 with the movement of production fluid up through the tubing. The gas pressure in the upper cylinder is determined by the depth of the pump assembly in the well.

Similar parts in the two modifications are identified by similar reference numerals and a detailed description thereof is omitted for simplicity.

From the above description the operation is believed to be clear for both modifications and it will be apparent that changes may be made Within the spirit of the invention as defined by the valid scope of the appended claims.

I claim:

1. A pump assembly for positioning in tubing of a Well casing by means of a cable comprising a top sub having means for securing a cable thereto and means to secure a gas receiving cylinder thereto, a gas receiving cylinder secured to said top sub in fluid tight relation, means to introduce gas under pressure into said gas receiving cylinder, a lift piston slidably mounted in said pressure cylinder, a center connecting sub secure-d to said gas receiving cylinder, a connecting rod secured to said lift piston and passing through said center connecting sub, means to provide a fluid-tight seal between said connecting rod and said center connecting sub, a pump seating nipple securing adjacent sections of tubing together, a pump cylinder secured to said center connecting sub, a pump piston in said pump cylinder and secured to said connecting rod, said pump seating nipple and center connecting sub being provided with openings providing communication between the fluid in the annular space between the casing and the tubing and one of said pistons, valve means normally closing the openings in said pump seating nipple, means to operate said valve means, a produced fluid passageway from said pump piston to one of said tubing and casing, check valve means in said pump assembly for preventing retrograde movement of said produced fluid, said pump assembly operating by filling the pressure cylinder with compressed gas to a desired pressure for the depth of fluid being pumped, applying pressure fluid to the other of said tubing and said casing in excess of the pressure in the pressure cylinder thereby moving the lift piston in a direction to operate said pump piston in a produced fluid raising direction and forcing such produced fluid through the passageway to the one of said tubing and casing whereby the produced fluid passes upwardly in the said one of said tubing and casing as pressure is intermittently exerted on the column of fluid in the other of said tubing and casing to cause the pressure piston and the pump piston to reciprocate.

2; A pump assembly for positioning in tubing of a well casing by means of a cable comprising a top sub having means for securing a cable-thereto and means to secure a gas' receiving cylinder thereto, a gas receiving cylinder secured to said top sub in fluid-tight relation, means to introduce gas under pressure intosaid gas receiving cylinder, a lift piston slidably mounted in said pressure cylinder, a center connecting sub secured to said gas receiving cylinder, a connecting rod secured to said lift piston and passing through said center connecting sub, means to provide a fluid-tight seal between said connecting rod and said center connecting sub, a pump seating nipple securing adjacent sections of tubing together, cooperating stop means on said pump seating nipple and center connecting sub to determine the seated position of said center connecting sub, a pump cylinder secured to said center connecting sub, a pump piston in said pump cylinder and secured to said connecting rod, said pump seating nipple and center connecting sub being provided with openings providing communication between the. .fluid in the annular space between the casing and the tubing and one of said pistons, valve means normally closing the openings in said pump seating nipple, cam means on said center connecting sub for operating the valves whereby when said center connecting sub is in proper position said valves are open to permit communication between the annular space surrounding the tubing and the said one piston, a produced fluid passageway from said pump piston to one of said tubing and casing, check valve means in said pump assembly for preventing retrograde movement of said produced fluid, said pump assembly operating by filling the pressure cylinder with compressed gas to a desired pressure for the depth of fluid being pumped, applying pressure fluid to the other of said tubing and said casing in excess of the pressure in the pressure cylinder thereby moving the lift piston in a direction to operate said pump piston in a produced fluid raising direction and forcing such produced fluid through the passageway to the one of said tubing and casing whereby the produced fluid passes upwardly in the said one of said tubing and casing as pressure is intermittently exerted on the column of fluid in the other of said tubing and casing to cause the pressure piston and the pump piston to reciprocate.

3. A pump assembly for wells adapted to be positioned in the tubing of a well casing by means of "a cable comprising a top sub having means for securing a cable to one end thereof, and means to receive a gas receiving cylinder to the other end, a gas receiving cylinder secured by one end to said top sub in fluid tight relation, a lift piston slidably mounted in said gas receiving cylinder, means to supply gas under pressure into said gas receiving cylinder, a cylinder connecting sub secured to the other end of said pressure cylinder and having a passage for pressure fluid in the tubing to operate said lift piston, a connecting rod secured to said lift piston and passing through said connecting sub, a pump seating nipple joining sections of the tubing and having means for attachment to adjacent sections of well tubing to connect adjacent sections of such well tubing together, a center connecting sub connected to said cylinder connecting sub, cooperating stop means on said pump seating nipple and said center connecting sub to determine the seated position of said center connecting sub, a pump cylinder secured to said center connecting sub, said pump seating nipple having openings providing communication between the fluid in the annular space between the casing and the tubing, registering passages in said center connecting sub and said pump seating nipple to permit the flow of fluid between the space surrounding said connecting rod and the inner periphery of the center connecting sub, valve means normally closing the communicating opening of said pump seating nipple, cam means on said center connecting sub for opening the valves in said pump seating nipple whereby when said center connecting sub is in proper position said valves are open to permit communication between the annular space surrounding the tubing and the annular space surrounding the connecting rod, a pump piston secured to said connecting rod and slidably mounted in said pump cylinder, a produced fluid pasageway through said pump piston, a check value preventing downward movement of fluid through said produced fluid passageway of said pump piston, a bottom sub secured to said pump cylinder and having a passage for produced fluid, a check valve in said bottom sub for preventing downward movement of said produced fluid, said pump assembly operating by filling the pressure cylinder with compressed gas to a desired pressure for the depth of fluid being pumped, applying pressure fluid to the tubing in excess of the pressure in the pressure cylinder thereby moving the lift piston toward said top sub and thereby moving the pump piston and forcing produced fluid through the passages in the connecting sub and in the pump seating nipple whereby the produced fluid passes upwardly in the space between the tubing and the casing 'as pressure is intermittently exerted on the 6 column of fluid in the tubing to cause the pressure piston and the pump piston to reciprocate.

4. A pump assembly for wells adapted to be positioned in the tubing of a well casing by means of a cable comprising a top sub having means for securing a cable and a gas receiving cylinder thereto, a gas receiving cylinder secured to said top sub in fluid tight relation, a lift piston slidably mounted in said pressure cylinder, a piston rod secured to said lift piston and extending away from said top sub, a center connecting sub slidably receiving said connecting rod and secured to said gas receiving cylinder, a pump seating nipple securing adjacent sections of tubing together, cooperating stop means on said pump seating nipple and said center connecting sub to determine the seated position of said center connecting sub and the pump assembly secured thereto, said pump seating nipple being provided with openings providing communication between the fluid in the annular space between the casing and the tubing and the lift piston, valve means to control said openings whereby when said center connecting sub is in proper position said valves may be operated to permit communication between the annular space surrounding the tubing and the annular space surrounding the connecting rod within said gas receiving cylinder, a pump cylinder secured to said center connecting sub, a pump piston secured to said connecting rod and slidably mounted in said pump cylinder, a produced fluid passageway through said pump piston and said connecting rod, a check valve in said passageway through said pump and piston preventing retrograde movement of fluid, an inner tube connected to said top sub and extending into the passageway through said connecting rod, said top sub being provided with passage means communicating with said inner tube, and other check valve means in said inner tube and top sub to prevent retrograde movement of produced fluid, said pump assembly operating by filling the pressure cylinder with compressed gas to a desired pressure for the depth of fluid being pumped, applying pressure to the fluid in the casing in excess of the pressure in the pressure cylinder thereby raising the lift piston upwardly and thereby moving the pump piston upwardly raising the produced fluid and forcing such produced fluid through tubing.

5. A pump assembly for use within the tubing of a well having a casing comprising an upper sub to support the assembly from a cable, said assembly including a first cylinder secured to said upper sub, a first piston in said first cylinder, a center connecting sub secured to the other end of said first cylinder, a connecting rod passing through said center connecting sub and secured to said first piston, sealing means between said first piston and said first cylinder whereby a predetermined amount of compressed gas can be forced into said first cylinder, a second and pump cylinder connected to said center connecting sub, a second and production fluid pump piston mounted on said connecting rod and positioned in said second cylinder for operation from said first piston, sealing means between said piston rod and said center connecting sub for separating fluid for operating said first piston from communication with produced fluid from said second piston, said center connecting sub having 'a chamber for communication through apertures in the tubing with the annular space between the casing and tubing, sealing means for providing a fluid tight seal between said center connecting suband the tubing including sealing means on opposite ends of the chamber of said center connecting sub thereby providing independent communication between one of said cylinders and one of the interior of the tubing above said pump assembly and the annular space between said casing and tubing and independent communication between the other of said cylinders and the other of the interior of the tubing and the annular space between said casing and tubing whereby a pulsing action of the fluid in one of the interior of the tubing above said pump assembly and the annular space between said casing and said tubing will operate said first cylinder and thereby operate said pump cylinder whereby produced fluid may be pumped out of one of the interior of said tubing and the annular space between said casing and tubing, check valve means in association with said pump cylinder to cause production fluid entering the free end of said pump cylinder to be forced upwardly from the upper end of said pump cylinder.

6. The invention according to claim 5 in which a valve and plug means are provided to confine the gas under pressure in said first cylinder.

7. The invention according to claim 5 in which the pump assembly is mounted in a tubing string and stop means are provided in the tubing string adjacent the aperture in the tubing string for communication with the chamber in said center connecting sub.

8. The invention according to claim 7 in which valves are provided for closing the apertures in the tubing string in communication with the chamber in the center connecting sub.

9. The invention according to claim 5 in which the pump assembly is mounted in a tubing string having apertures therethrough for communication with the chamber in the center connecting sub and sealing means are provided between the tubing and the casing below the apertures in the tubing in communication with the chamber in the center connecting sub.

10. The invention according to claim 5 in which the pump assembly is mounted in a tubing string and a seal is provided between the tubing string and the casing below the apertures in the tubing string in communication with the chamber in the center connecting sub and operating fluid for compressing the gas in the first cylinder is carried by the tubing and the produced fluid is carried by the space between the tubing and the casing.

11. The invention according to claim 5 in which the pump assembly is mounted in a tubing string having apertures in communication with the chamber in the center connecting sub and the operating fluid for compressing the gas in the first cylinder is confined between the tubing and the casing and a seal between the tubing and the casing below said apertures in the tubing and the piston rod is tubular and the produced fluid passes through such tubular piston rod into the tubing above the pump assembly.

12. The invention according to claim 5 in which the pump assembly is mounted in the tubing string with apertures in the tubing string in communication with said chamber in said center connecting sub and the operating fluid for compressing the gas in the first cylinder is confined in the space between the tubing and the casing of the well and a seal below said apertures in the tubing in communication with the chamber in said center connecting sub whereby the produced fluid is conducted through the tubing above said pump assembly.

13. A tubing and pump assembly for use with a well casing for producing production fluid comprising a center connecting sub, tubing connected to said center connecting sub and extending upwardly and downwardly therefrom, means providing a first cylinder extending upwardly from said center connecting sub, a first piston in said first cylinder, a piston rod connected to said first piston and passing through said center connecting sub whereby a predetermined amount of compressed gas can be forced into said first cylinder, means providing a second and pump cylinder connected to said center connecting sub and extending downwardly therefrom, a second and production fluid piston mounted in said second cylinder and connected to said piston rod for operation of said second piston from said first piston, sealing means between said piston rod and said center connecting sub for separating fluid for operating said first piston from communication with produced fluid from said second piston, said center connecting sub having a chamber for communication through apertures with, the annular space between the casing and tubing, sealing means providing independent communication between one of said cylinders and one of the interior of the tubing above said pump assembly and the annular space between said casing and tubing and independent communication between the other of said cylinders and the other of the interior of the tubing and the annular space between said casing and tubing whereby a pulsing action of the fluid in one of the interior of the tubing above said pump assembly and the annular space between said casing and said tubing will operate said first cylinder and thereby operate said pump cylinder whereby produced fluid may be pumped out of one of the interior of said tubing and the annular space between said casing and tubing, check valve means in association References Cited by the Examiner UNITED STATES PATENTS 832,726 10/1906 Feeny 103-204 2,101,218 12/1937 Hufl 103-46 X 2,384,173 9/1945 Johnson 10346 2,562,584 7/1951 Sobeng 10346 ROBERT M. WALKER, Primary Examiner. 

1. A PUMP ASSEMBLY FOR POSITIONING IN TUBING OF A WELL CASING BY MEANS OF A CABLE COMPRISING A TOP SUB HAVING MEANS FOR SECURING A CABLE THERETO AND MEANS TO SECURE A GAS RECEIVING CYLINDER THERETO, A GAS RECEIVING CYLINDER SECURED TO SAID TOP SUB IN FLUID TIGHT RELATION, MEANS TO INTRODUCE GAS UNDER PRESSURE INTO SAID GAS RECEIVING CYLINDER, A LIFT PISTON SLIDABLY MOUNTED IN SAID PRESSURE CYLINDER, A CENTER CONNECTING SUB SECURED TO SAID GAS RECEIVING CYLINDER, A CONNECTING ROD SECURED TO SAID LIFT PISTON AND PASSING THROUGH SAID CENTER CONNECTING SUB, MEANS TO PROVIDE A FLUID-TIGHT SEAL BETWEEN SAID CONNECTING ROD AND SAID CENTER CONNECTING SUB, A PUMP SEATING NIPPLE SECURING ADJACENT SECTIONS OF TUBING TOGETHER, A PUMP CYLINDER SECURED TO SAID CENTER CONNECTING SUB, A PUMP PISTON IN SAID PUMP CYLINDER AND SECURED TO SAID CONNECTING ROD, SAID PUMP SEATING NIPPLE AND CENTER CONNECTING SUB BEING PROVIDED WITH OPENINGS PROVIDING COMMUNICATION BETWEEN THE FLUID IN THE ANNULAR SPACE BETWEEN THE CASING AND THE TUBING AND ONE OF SAID PISTONS, VALVE MEANS NORMALLY CLOSING THE OPENINGS IN SAID PUMP SEATING NIPPLE, MEANS TO OPERATE SAID VALVE MEANS, A PRODUCED FLUID PASSAGEWAY FROM SAID PUMP PISTON TO ONE OF SAID TUBING AND CASING, CHECK VALVE MEANS IN SAID PUMP ASSEMBLY FOR PREVENTING RETROGRADE MOVEMENT OF SAID PRODUCED FLUID, SAID PUMP ASSEMBLY OPERATING BY FILLING THE PRESSURE CYLINDER WITH COMPRESSED GAS TO A DESIRED PRESSURE FOR THE DEPTH OF FLUID BEING PUMPED, APPLYING PRESSURE FLUID TO THE OTHER OF SAID TUBING AND SAID CASING IN EXCESS OF THE PRESSURE IN THE PRESSURE CYLINDER THEREBY MOVING THE LIFT PISTON IN A DIRECTION TO OPERATE SAID PUMP PISTON IN A PRODUCED FLUID RAISING DIRECTION AND FORCING SUCH PRODUCED FLUID THROUGH THE PASSAGEWAY TO THE ONE OF SAID TUBING AND CASING WHEREBY THE PRODUCED FLUID PASSES UPWARDLY IN THE SAID ONE OF SAID TUBING AND CASING AS PRESSURE IS INTERMITTENTLY EXERTED ON THE COLUMN OF FLUID IN THE OTHER OF SAID TUBING AND CASING TO CAUSE THE PRESSURE PISTON AND THE PUMP PISTON TO RECIPROCATE. 